Written By: Mitch Altman
Heat gun (1)
TV-B-Gone Kit (1)
or hair drver, or liahter
Baseball cap (1)
Hot glue gun (1)
or anv other hat with a visor
Tactile switch (1)
Needlenose pliers M)
Heat-shrink tubinq (1)
Heat-shrink tubing (1)
Wire (about 2")
Permanent marker (1)
"Hey, you mind turning that thing off?" Simple enough question, but I got tired of people
looking at me like I'm from Mars. When a TV is on in the room, I can't think. I just stare at
the thing and drool.
So I invented TV-B-Gone, a key chain that stealthily turns off just about any television.
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When the TVs turn off, people turn on, engage in conversation, read, eat, and perform all
sorts of human activities. Peace happens.
I recently teamed up with prolific kit maker Limor Fried to create a $20 kit version of the
original TV-B-Gone key chain. This version works up to 40 yards away, and it's totally
hackable; the entire project is open source and documented at
http://ladvada.net/make/tvbaone . Here's how I built one into a baseball cap that lets me look
at almost any TV, touch the top, and watch with glee as it shuts off.
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Step 1 — How TV-B-Gone Works
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1.2 milliseconds on-time
1.0 milliseconds off-time
7.1 milliseconds on-time
27.8 milliseconds off-time
1.2 milliseconds on-time -
1.0 milliseconds off-time -
7.1 milliseconds on-time -
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• TV remote controls all work the
same way: by transmitting coded
patterns of 940nm wavelength
infrared to the television's remote
control receiver, somewhat like
sending Morse code with a
flashlight. The receiver watches for
blinking IR, and when it sees
patterns it recognizes, performs
the corresponding functions on the
TV. To avoid accidental triggering
by reflected light in the room,
receivers only respond to IR light
that pulses at a specific carrier
• For our TV-B-Gone, we don't care
about couch-surfing functionality;
all we need is the code for turning a
TV off. (Because remotes have just
one on/off button, this is the same
as the code to turn it on, and the
TVs current state determines
which new state to toggle to.)
• For example, to turn off a JVC TV,
you blink the pattern shown in
Figure A using a carrier frequency
of 54kHz. The entire sequence
lasts only a tiny fraction of a
second, so there's no perceivable
• Different manufacturers' IR
standards vary, but they all use
rapid blinking of an even faster
carrier frequency. TV-B-Gone
transmits the on/off button codes
for most TVs, one right after the
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other. So it works like other
remotes, but with just one button.
Step 2 — Assemble the kit.
• First I built the TV-B-Gone kit itself. I already knew how to do this, but you can follow the
excellent instructions at ladyada.net/make/tvbgone .
Step 3 — Install the switch.
• Take out the batteries and unsolder
the battery leads from the board.
Then bend the 4 legs of the tactile
switch apart so they're flat, and
hot-glue the switch to the button on
top of the cap.
• Use needlenose pliers to push
some of the wire-wrap wire through
the hat fabric near the button. Pull
enough wire through on the
underside of the hat to reach the
end of the visor.
• Repeat using a second piece of
wire, then solder the wires to 2 of
the switch's legs on the same side,
clip off the other 2 legs, and cover
the soldered joints with 1/16" heat-
• If you use a lighter, be careful not
to place the tubing (or the hat)
directly in the flame. Hold the flame
just above the tubing and move it
around slowly until it's fully shrunk.
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Page 5 of 9
• Use a needle and thread to sew the
2 wires to the inside of the hat. I
used 5 loops for each, tying them
off with a square knot.
Alternatively, you can also use hot
• Position the assembled TV-B-Gone
at the edge of the visor of the hat,
with the IR emitters just inside the
brim, pointing outward. Cut the
wires from the hat-top switch so
they extend just past the switch
button on the circuit board.
Step 6 — Install the battery pack.
• Center the battery pack under the cap's dome with its 2 wires facing forward, toward the
visor. Hot-glue the battery pack in place, then sew (or hot-glue) its wires to follow the
same paths as the switch wires.
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Step 7 — Install the TV-B-Gone.
• Trim and solder the wires to the
battery terminals on the circuit
board (BATT), red to + and black to
-, covering the connections with
1/16" heat-shrink tubing.
• Trim and solder the 2 wires from
the tactile switch and solder them
to the 2 connected terminals for the
onboard switch (S1). It does not
matter which wire goes to which
Step 8 — Test.
• Insert 2 batteries into the holder. The visible LED (LED5) should start blinking. If not,
immediately take the batteries out and check that the battery leads aren't reversed.
• You can also confirm that all 4 of the TV-B-Gone's IR emitters are blinking by watching
them through a digital camera (most cameras can see IR).
• After the TV-B-Gone turns itself off, pushing the button on top of the hat should restart the
transmission sequence. If not, double-check the wires running from the hat switch to the
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Step 9 — Final assembly.
• Remove the batteries, then cover
the circuit board with a 2"-long
piece of 1" heat-shrink tubing and
shrink it in place.
• After shrinking, cut little pieces out
of the tubing to expose the visible
light and the onboard switch.
• Hot-glue the covered board to the
underside of the visor with the IR
emitters facing forward, as before.
Finally, use a colored marker or
paint to conceal the silver parts of
the hat switch.
Step 10 — A Real-Life TV Story
• We walk into a restaurant. Nice place — except there are 3 huge-screen TVs blaring from
different corners. No one is watching any of them, so off they go. None of the customers
even seem to notice, yet the waiter feels obliged to turn them back on.
• No problem — off they go again. The waiter calls the manager, who grabs the remote
control and turns them on again. Triumphant, they start to walk away. Off go the TVs once
more. While they're standing there, dumbfounded, I switch them all on. Then off. Their
shoulders slump in unison, admitting defeat. We enjoy our meal and conversation.
• I love my TV-B-Gone hat.
This project first appeared in MAKE Volume 13 .
Related Posts on Make: Online:
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Double the Range of Your TV-Be-Gone
last generated on 2012-1 1-03 01:11:26 AM.
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